1. Field of the Invention
The present invention relates to a portable terminal, and more particularly to a sliding-type portable terminal having a pair of housings which can be slidably coupled with each other.
2. Description of the Related Art
In general, portable terminals refer to devices which serve users with a mobile communication function. Recently, portable terminals have not only been used as mobile communication devices, but have also played the role of multimedia devices to reproduce music files, moving picture files, etc., and financial service devices for micro payment, mobile banking, etc., to provide complex functions.
Such portable terminals may be classified into various types according to their appearance, such as a bar-type portable terminal, a flip-type portable terminal, a folder-type portable terminal, etc. Recently, sliding-type portable terminals have appeared, and have shared most of the portable terminal marketplaces along with folder-type portable terminals.
A bar-type portable terminal has a single body housing on which a data input/output unit, a transmitter, a display unit, and a receiver are mounted. A bar-type portable terminal has an advantage of having a simple configuration where all elements are embedded in a single body housing to provide mobile communication functions. However, there is limitation in miniaturization of a bar-type portable terminal because it is difficult to secure a distance between the transmitter and receiver in order to carry out voice communication.
A flip-type portable terminal has a structure where a flip is rotatably coupled with a bar-type portable terminal to close an input unit, such as a keypad, etc., in a communication-standby mode to prevent malfunction of the input unit. However, there is also a limitation in miniaturization of a flip type portable terminal because it is difficult to secure a distance between the transmitter and the receiver.
A folder-type portable terminal has a structure where a pair of housings can be rotatably coupled with each other and be folded. In folder-type portable terminals, an input unit and an output unit are arranged on two housings, respectively, thereby being useful for miniaturization of the folder-type portable terminals. Further, it is possible to secure a sufficient distance between the transmitter and the receiver. Consequently, folder-type portable terminals have had a significant market share of the portable terminal marketplaces for a long time.
A sliding-type portable terminal has a structure where a pair of housings can be slidably coupled with each other. In sliding-type portable terminals, an input unit and an output unit are arranged on housings, respectively. Especially, a keypad used as the input unit is opened and closed depending on sliding movement of the housings. Sliding-type portable terminals have advantages of preventing malfunction of the input unit, facilitating operation thereof, and miniaturization thereof. Accordingly, sliding-type portable terminals have made gradual inroads into the market for folder-type portable terminals, and now have a market share greater than folder-type portable terminals.
However, a conventional sliding-type portable terminal has a structure where one of housings should be manually opened and closed. Thus, there is inconvenience in which a user moves a housing of a sliding-type portable terminal in order to open and close sliding-type portable terminal. In addition, when a display unit is mounted on a sliding housing, there is a problem in that a user causes contamination of the display unit when the user touches a window of the display unit. Further, in order to solve this problem and to improve convenience of a user, a sliding-type portable terminal, in which housings are semi-automatically opened and closed, has been developed to overcome the disadvantage of the above-mentioned sliding-type portable terminal which is opened and closed manually. However, since a sliding-type portable terminal having a semi-automatic opening and closing mechanism also has a disadvantage in that a user has to directly move one of the housings beyond a predetermined distance, it is inconvenient for the user to use this type of sliding-type portable terminal.